026 Pro Hard Starting

[buddie]

I tried to search for a solution but the search function on this site isn't working. Saw won't start unless I prime the carb with 1/2 to 1cc of fuel, then it will start on first or second pull and runs fine until it is shut down. This is a low hour saw which has been well maintained but here is the extent of my troubleshooting so far:

Removed, disassembled and cleaned carb - all looks good

Pressure tested fuel and impulse lines, not softened or collapsing

Fuel filter picks up fuel well

Once running, low and high jets are responsive to adjustment

The stop-ground engages and disengages properly

Sinthered tank breather seems clean and clear

Sparkplug clean, gap OK

Air filter is clean, choke valve closes when engaged

Today though, there seems to be pressure in the fuel tank, hissing sound when cap is released. I don't know if this is because of the grief I have put the saw through today or because tank still has old style rubber pressure equalizing valve - could that be a problem or is this normal?


Is the throttle mechanism a common weak point of this saw? The plastic parts in the handle seem kind of cheesy to me and the action is not very responsive because when I switch the carb from full choke to half choke or run, the butterfly hangs up at a near full throttle position (scary) until I double-trigger, then butterfly will close.

I learned what happens when the clutch drum is not positioned properly on the oil pump carrier. One big oily clutch mess!

Sorry for the long post, I would really appreciate any input and suggestions anyone may offer me. I bet this website really comes alive this time of year when us 'backyard lumberjacks' come out of hiding in springtime.

Many Thanks!

 

[watsonr]

You said today you see pressure in the tank....your vent is bad, cheap fix, just replace it.

You stated that you cleaned the carb, did you put in a kit, may want to clean it again, you may have missed something?

Once at half choke you need to hit the trigger to switch to normal mode, its designed that way so that the saw can complete the warm up cycle, when that is complete or you think it is after a couple minutes, hit the trigger to close the throttle. Take off the air filter and watch it, your choke shaft may have a burr on it?

Welcome to the site!! 026 is a GOOD saw!

 

[buddie]

Thank you watsonr for the welcome and your reply. I guess the saw is behaving normally until I kick it down, I'm not used to it doing this and I'll need to adjust the carb better and get the rpms down at startup. You're right, the 026 is a great saw, I bought it new about 14 years ago and it has run well until this no start problem. I will put in a new carb kit in but the saw runs well, just starts hard (if at all). I took everything out except the welch plug and chased the thru ports. It ran well before I took it apart and it runs good now it just doesn't start without priming. Could the tank vent be a problem with hard start? Maybe it's me......I'm a 59 year old woman and everything's getting harder to start anymore. The decompression feature is a lifesaver for me.

 

[pioneerguy600]

After 14 years it is about time to have the carb kitted, the soft parts like the diaphragms get worn and streatched after long periods in todays fuels. The tank vent is working properly, they are designed to allow air to enter the tank but not to allow pressure/air to escape from the tank ,hence the tank will become pressurised. The carb pop off spring is designed to work properly under these conditions.

 

[buddie]

Thanks for your reply pioneerguy600 - I am in the process of learning more about the chainsaw. As with anything else, it turns out you really don't know much about something at all, until it breaks and needs repair. I have more experience with automobile carburetors but the simplicity of the Walbro is actually a greater mystery with it's micro porting and few parts. What is a carb pop off spring? I have never had to remove a welch plug before, is it important to do so on this carb? I'm going to get this thing working if it kills me.....
Thanks.

 

[buddie]

Just thought I'd make a note that this problem has been solved in the event it may help someone else. To make a long story very short, I took saw mostly apart, did compression, vacuum and pressure testing, replaced common maintenance parts and seems I have a very healthy saw but during dis-assembly I noticed that the rubber intake boot was not clamped to the head tightly enough. After putting saw back together today, it fired on second pull and ran like a champ.

Just wanted to thank you all for your help